One vertex per element, one color per generator, with an edge from x to x·s.
(2,6)(7,8)(9,10,15,14)(11,18,13,16)(12,17,21,22)(19,24,20,23)(25,26)(27,31)(28,32)(29,39)(30,34)(33,37)(35,40)(36,38)(1,2,5,6)(3,7,4,8)(9,11,15,13)(10,16,14,18)(12,20,21,19)(17,24,22,23)(25,27)(26,31)(28,37)(29,36)(30,35)(32,33)(34,40)(38,39)(1,3,5,4)(2,7,6,8)(10,14)(11,13)(17,22)(19,20)(27,35)(29,37)(31,40)(33,39)(1,3,5,4)(2,7,6,8)(9,12,15,21)(10,17,14,22)(11,19,13,20)(16,23,18,24)(25,28)(26,32)(27,29)(30,36)(31,39)(33,40)(34,38)(35,37)(1,3,5,4)(2,7,6,8)(9,13,15,11)(10,18,14,16)(12,20,21,19)(17,24,22,23)(25,29)(26,33)(27,36)(28,35)(30,37)(31,32)(34,39)(38,40)(1,4,5,3)(2,8,6,7)(9,14,15,10)(11,18,13,16)(12,17,21,22)(19,23,20,24)(25,26)(27,31)(28,38)(29,33)(30,34)(32,36)(35,40)(37,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.